Refrigerant condenser arrangement



Jan. 6, 1970 J, NORTON 3,487,642

REFRIGERANT CONDENSER ARRANGEMENT Original Filed Jan. 24, 1967 2Sheets-Sheet 1' mvsmon. John 1? A/arzan Jan. 6, 1970 J. P. NORTON 3, 7,

REFRIGEHANT CONDENSER ARRANGEMENT Original Filed Jan. 24, 1967 2Sheets-Sheet 2 54 453 I/ &

Fig. 2

INVENTOR- Jobn E lib/t0? United States Patent ABSTRACT OF THE DISCLOSUREThe present invention relates to fluid condenser systems andmoreparticularly relates to condenser arrangements including at least twodifferent fluid paths and cooperative valve means for simultaneouslycontrolling the flow conditions in a stream of pressurizedvaporizable-condensible working fluid passed through condenser means andregulating the effective condensing area in response to change incondition of the fluid emitted from the condenser.

CROSS-REFERENCE TO RELATED APPLICATIONS The present invention relates,in part, to co-pending application S.N. 516,641 filed Feb. 18, 1966 byHarold L. Kirk and John P. Norton, now US. Patent 3,365,133, and thepresent application is a division of application Ser. No. 611,300, filedJ an. 24, 1967 and which is now Patent No. 3,430,453.

BACKGROUND OF THE INVENTION In refrigeration systems of the type where avaporizable-condensible refrigerant is circulated through a fluid flowcircuit including cooperatively connected compressor, condenser,expansion device, and evaporator, the pressure, temperature, and flowrate of refrigerant through the circuit are interrelated and affectsystem performance. This is because the refrigerant pressure at thecompressor outlet significantly influences the pressure at the inlet ofthe refrigerant expansion device so, for example, a decrease in pressuredecreases the rate of flow of refrigerant through the expansion deviceto substantially reduce the refrigerating capacity of the system.Furthermore, in such previous refrigeration systems the pressure of therefrigerant emitted from the condenser has been related to thetemperature of the cooling medium supplied to the condenser so anuncontrolled decrease in temperature of the cooling medium supplied tothe condenser results in reduced pressure in the refrigerant emittedfrom the condenser, and vice versa, regardless of the cooling demands onthe system.

Previous refrigeration systems have provided various complicated,expensive arrangements to maintain optimum compressor dischargepressure. One such previous arrangement has included means to controlthe pressure of the refrigerant emitted from the compressor in responseto change in the temperature of the cooling medium supplied torefrigerant condenser while other arrangements have directly controlledcompressor discharge pressure regardless of refrigerant pressure at theexpansion device.

In other methods, heat is added to the refrigerant to selectivelyincrease the temperature, and pressure, of the refrigerant at thecompressor outlet or the temperature or flow rate of the cooling mediumsupplied to the refrigerant condensing means, for example ambient air,is regulated to control the temperature of the refrigerant within thecondenser.

In some cases, means have provided to flood selected 3,487,642 PatentedJan. 6, 1970 ice portions of the condenser with refrigerant inaccordance with the pressure at the outlet of the compressor to reducethe effective heat transfer area of the condenser and correspondinglydecrease the heat loss by the refrigerant to increase refrigerantpressure. Such arrangements provide sluggish control and response tochange in conditions is slow because the condenser must be drained orfilled in accordance with changes in refrigerant pressure and the timerequired for draining or filling the condenser is significant.

Another method previously used to control the outlet pressure from therefrigeration compressor has included dividing the refrigerant flowemitted from the compressor between at least two separate condensers inaccordance with the pressure at the outlet of the compressor. Sucharrangements require cooperative valve and control means at thecompressor outlet to control the quantity of compressed refrigerantflowing to the selected condensers. Such refrigerant flow control is notdirectly and rapidly responsive to change in condenser pressure ortemperature at the condenser outlet nor do such systems provide means tocontrol the quality or flow rate of refrigerant supplied to theexpansion device.

SUMMARY OF THE INVENTION It has been recognized that the presentinvention provides a straightforward, inexpensive condenser andcondenser control arrangement for use in a closed fluid circuit toefficiently control the condition of vaporizablecondensible workingfluid emitted from a condenser in response to changes in the conditionof the working fluid at the condenser outlet. Moreover, the presentinvention provides a straightforward refrigerant control arrangementwith a minimum number of moving parts to simultaneously sense thecondition of the refrigerant at the condenser outlet and control therefrigerant flow rate and effective condensing area without complicatedinterrelated valve and control apparatus.

Furthermore, it has been recognized that the present invention providesa valve arrangement which not only improves the operability of thesystem and uniformly controls the quality of the refrigerant supplied tothe expansion device but also simultaneously maintains the refrigerantpressure at the compressor outlet pressure within selected limits.

It has been further recognized that the present invention provides acondenser arrangement which can be applied in fluid flow circuits of thegeneral type where a vaporizable-condensible Working fluid is condensedand it is desirable to control the pressure within a selected portion ofthe circuit, the rate of condensation of working fluid and/or thecondition of the working fluid at the outlet of the condenser. Forexample, an advantageous condenser arrangement in accordance with thepresent invention can be used to control the condition of working fluidemitted from a condenser in an air heating apparatus Where heatedvaporizable-condensible working fluid is circulated through a fluid flowcircuit and is provided to a condenser to heat a stream of air.

Various other features of the present invention will become obvious toone skilled in the art upon reading the disclosure set forthhereinafter.

More particularly, in a heat exchange fluid flow circuit Where avaporizable-condensible working fluid is circulated through a circuitincluding means to alternately vaporize and condense the fluid, thepresent invention provides an improved condenser arrangement comprising:condenser means having at least two separate flow conduits to conductworking fluid through the condenser, each conduit having an inlet tocommunicate with means to vaporize said working fluid, and a workingfluid outlet;

valve means including an elongated casing having a working fluid outletand working fluid inlet ports communicatively connected to outlets ofselected flow conduits of said condenser; piston means to movelongitudinally through the casing to close selected working fluid inletports; and, means to move the piston in the casing to control suchselected working fluid inlets in response to condition of working fluidadmitted to the casing from the condensing means.

It will be appreciated by those skilled in the art that various changescan be made in the arrangement, construction or form of the condenserarrangement disclosed herein without departing from the scope or spiritof the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS condenser arrangement in accordancewith the present invention; and

FIGURE 4 is a view, in section, showing an example of atemperature-responsive valve arrangement which can be used in acondenser arrangement in accordance with the present invention.

DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION FIGURE 1 shows acondenser 2 and valve 3, in accordance with the present invention,provided in an example of a flow circuit including a compressor 1,refrigeration expansion valve 4 and an evaporator located in a space tobe conditioned. In operation of the refrigeration system as shown inFIGURE 1 refrigerant is pumped from the outlet of compressor 1 tomanifold 8 and the com-.

pressed refrigerant flows through the selectively open conduits ofcondenser 2 so at least a part of the refrigerant is condensed and thecondensed refrigerant is supplied to an expansion device 4. Inaccordance with one feature of the present invention an arrangement isprovided to simultaneously regulate the refrigerant flow rate andcondensing area so the pressure of the refrigerant supplied to expansionvalve 4 is relatively constant and the cooling capacity of therefrigeration system is relatively unaffected by conditions prevailingin the cooling medium supplied to the condenser.

Condenser 2 includes an inlet manifold 8 to receive compressedrefrigerant from the outlet of the compressor by means of a conduit 7.In accordance with one feature of the present invention, condenser 2includes at least two separate flow conduits, and in the example ofFIGURE 1 four separate flow conduits 9, 11, 12, and 13 are provided.Each conduit has an inlet communicating with manifold 8 and a separateoutlet connected to valve 3 as hereinafter described.

A conduit 15 is provided to connect outlet 14 of valve 3 with anexpansion device 4 to provide expanded cooled refrigerant to anevaporator coil 5 located in space 6 to be served by the refrigerationsystem. Refrigerant is returned from evaporator 5 to the inlet ofcompressor 1 by means of a refrigerant return conduit 17.

FIGURE 3 is a view, in section, of one example of a valve 3 which can beused in a condenser arrangement in accordance with the present inventionand includes an elongate outer casing 10 having refrigerant inlet ports9a, 11a, 12a, and 13a, in longitudinally spaced relation in the side ofthe casing. In accordance with one feature of the present invention,each of the inlet ports 9a, 11a, 12a and 13a is connected to the outletof a separate conduit of condenser 2, for example conduits 9, 11, 12,and 13 respectively.

A piston 21 is cooperatively adapted to move in longitudinal slidingrelation within casing 10 to advantageously control the opening andclosing of a number of the inlet ports and divide casing 10 intochambers 27 and 28 on either side of the piston in accordance with theposition of the piston in casing 10. Chamber 28 can be provided toreceive piston 21 under selected conditions so none of the inlet portsare covered and closed and in response to a selected change in conditionof refrigerant piston 21 can move freely out of chamber 28 to coverselected inlet ports. In the example of FIGURE 3, piston 21 canadvantageously be long enough to cover only inlet ports 9a, 11a, 12a anda stop 20 can be disposed, as shown, in casing 10 to restrict themovement of piston 21 so inlet 13a is never closed and a minimumrefrigerant fiow is assured.

Piston 21 can be of straightforward construction using a cylindricalsection of selected length dependent on the spacing between inlet ports9a, 11a, 12a, 13a, and the number of such ports to be open or closed atany one time. In the example of FIGURE 3, piston 21 includes machined orrolled circumferential grooves (not shown) for receiving O-rings 22 ofsuitable materials, for example Teflon, to restrict leakage ofcompressed refrigerant past piston 21.

Piston 21 advantageously moves freely in casing 10 as hereinbeforedescribed to close or open selected compressed refrigerant ports inaccordance with the disposition of the inlet ports and the position ofpiston 21 in casing 10. Means, for example a spring 23, can be providedto maintain selected force on one end of piston 21. In the example asshown in FIGURE 3, spring 23 can be a compression spring where the forceexerted by the spring varies with the extent of compression of thespring to provide a variable force on one side of piston 21 andadvantageously urge piston 21 through housing 10 toward refrigerantoutlet 14 of casing 10.

A gas bleed outlet 16 can be provided from chamber 28 for the escape ofthe compressed refrigerant which leaks past piston 21. A pressureresponsive relief valve 16a can be provided at outlet 16 to control therate at which refrigerant escapes from chamber 28 to provide arelatively constant back pressure within chamber 28 so movement ofpiston 21 through casing 10 is unaffected by the rate at whichrefrigerant leaks past piston 21.

When a pressure responsive valve as shown in FIG- URE 3 is used in arefrigerant circuit as shown in FIG- URE 1, refrigerant entering chamber27 exerts a force on the other end of piston 21 to urge the piston in adirection to compress spring 23 and open inlet ports where the forceexerted by the spring increases with increased refrigerant pressure sothe piston assumes balanced position in casing 10 dependent on thepressure of the refrigerant entering chamber 27. Selection of amechanical spring means 23 with known loading characteristics providesan arrangement where the piston will move to a prescribed position incasing 10 in response to selected refrigerant pressure in chamber 27 andwill respond predictably to change in pressure of the refrigerant toopen or close refrigerant inlets 9a, 11a, and 12a. For example, as thepressure of the compressed refrigerant emitted from condenser 2 isdecreased, the force exerted on the end of piston 21 by the fluidentering chamber 27 is diminished, so the piston 21 moves in casing 10in response to the force of spring 23 to cover additional refrigerantinlet ports and shut off the flow of refrigerant through thecorresponding conduits of condenser 2. On the contrary, when thepressure in condenser 2 is increased, piston 21 is urged in an oppositedirection to open additional conduits through condenser 2 to increasethe flow of refrigerant. It will be noted that as additional conduitsare opened in response to increased refrigerant pressure, the pressuredrop through the condenser is decreased and the condensing area ofcondenser 2 is simultaneously increased to provide additional heattransfer area so the refrigerant is cooled to decrease the refrigerantpressure at the outlet of condenser 2 and compressor 1.

FIGURE 4 is a view, in section, showing another eX- ample of a valvewhich can be used in a condenser arrangement provided by the presentinvention. The valve as shown in FIGURE 4 is responsive to thetemperature of the refrigerant admitted to chamber 37 from condenser 2of the refrigeration system of FIGURE 1 and is in some respects similarto the pressure responsive valve as shown in FIGURE 3 in that itincludes an elongate outer casing a having longitudinally spaced inletports 9b, 11b, 12b, and 13b where each inlet port communicates withconduits 11, 12, and 13 respectively, of condenser 2. A piston 31 isadapted to move through casing 10a to close or open selected number ofinlet ports and divide casing 10 into chambers 37 and 38 where chamber38 is adapted to receive piston 31 under selected conditions so thatnone of the inlet ports are closed.

Piston 31 can be of selected length to block a selected number of inletports and, as in the example of the vlave of FIGURE 3, piston 31 is longenough to cover ports 9b, 11b, and 1217. Also, as in the example of thevalve of FIGURE 3, a stop 36 can be provided in casing 10 to preventpiston 31 from blocking all of the inlet ports to completely stop theflow of refrigeration through condenser 2.

Piston 31 is similar to piston 21 of FIGURE 3 and can be ofstraightforward construction using a cylindrical section with groovesmachined or rolled for receiving O-rings 32 of a suitable material, forexample Teflon. O-rings 32 are provided to restrict flow of refrigerantpast piston 31, but a small amount of leakage is likely to occur sobleed port 16 can be provided and is connected to the inlet ofcompressor 1 by means of conduit 18. It is desirable to provide gasbleed means such as outlet 16 and conduit 18 even if no refrigerantleaks past piston 31 because movement of piston 31 causes relatedexpansion and contraction of chambers 37 and 38 and the gas flowresulting from change in chamber must be accommodated without affectingthe movement of the piston. Since a small amount of refrigerant leakagecan be accommodated and O-ring seals can be used, the relative machinetolerance for piston 31 and valve casing 10 are not restrictive and thepiston can be adapted to move freely through casing 10.

In the example of a valve 3 as shown in FIGURE 4, piston 31 can be movedin casing 10 by a temperature responsive actuator 34, for example atemperature responsive actuator manufactured under the trade name Elacby Standard-Thompson Company, where a change in the temperature ofrefrigerant entering the valve causes a change in linear dimension ofthe actuator to move the piston. Actuator 34 is supported in casing 10by mounting block 37 and piston 31 can be fastened to actuator 34, or,as shown in the example of FIGURE 3, piston 31 can merely rest onactuator 34. The Elac temperature responsive actuator of the example ofFIGURE 4 includes a piston 34a which is forced from housing 34b inresponse to an increase in temperature. The housing can include asubstance having a high coeflicient of thermal expansion to obtain asignificant movement of piston 34a with relatively little change intemperature. Some temperature responsive actuators, for example theactuator where piston 34b is filled with material having highcoefficient of thermal expansion, do not provide means to re turn thepiston to the housing in response to decreased temperature, so a spring33 can be provided to supply the return force necessary tosimultaneously reposition both piston 34a in housing 34 and piston 31 incasing 10. As distinguished from spring 23 of the embodiment of FIGURE 3which advantageously causes movement of piston 21 spring 33 prevents anymovement of piston 31 in casing 10a in response to change in refrigerantpressure in chamber 37. In a valve as shown in the example of FIGURE 4where the piston movement is controlled by thermal element 34 andrestricted by a spring 33 it is not necessary to provide absolutecontrol of the gas pressure in chamber 38' on the inactive side of thepiston because the actuator is responsive to temperature and provides asignificant operating force to overcome a slight imbalance in gaspressure across the piston. However, as discussed previously, means, forexample a bleed 16, can be provided to prevent the build-up ofsignificant gas pressure or vacuum in chamber 38 which, if uncontrolled,could develop suflicient force to adversely affect the responsiveness ofthe piston 31 to change in temperature of refrigerant entering casing10a.

In the refrigeration system as shown in FIGURE 1, which can include avalve as shown in the example of FIGURE 4, the flow of refrigerantthrough condenser 2 is controlled by temperature of the refrigerantemitted from condenser 2. It will be noted that the temperature of therefrigerant emitted from condenser 2 decreases with a decrease intemperature of cooling medium for example air, supplied to condenser 2or with a decrease in the temperature of refrigerant emitted fromcompressor 1. A decrease in refrigerant temperature is sensed by thermalresponsive element 34 of valve 3 and the element permits withdrawal ofpiston 31 in casing to close additional inlet ports in casing 10a. Theflow of refrigerant through condenser 2 is thereby restricted so theoutlet pressure of compressor 1 is increased and the effectivecondensing area of condenser 2 is decreased so the temperature and thepressure of the refrigerant emitted from condenser 2 are increased. Onthe other hand as the refrigerant temperature is increased, temperatureresponsive element 34 expands and piston 31 is moved in an oppositedirection in casing 10a to open additional flow conduits of condenser 2to increase the flow of refrigerant from compressor 1 and decrease thepressure and temperature of the refrigerant.

As stated hereinbefore, the arrangement in accordance with the presentinvention can be used in any application where a working fluid isvaporized and condensed in a fluid flow circuit. FIGURE 2 is a schematicdiagram of an air heating device including a condenser arrangement inaccordance with the present invention. The heater illustrated in FIGURE2 includes a vaporized working fluid generator 41 having an integralheat source and a boiler to provide vaporized working fluid at selectedpressure. The air heating device can further include a fluid responsiveengine 42 driven by pressurized working fluid emitted from generator 41as hereinafter described. In accordance with the present invention,condenser 40 receives heated working fluid and transfers the heat to theair passed through condenser 40 in heat exchange relation.

The heater as shown in the example of FIGURE 2 is self-powered so anauxiliary source of power, other than vaporized fluid generator 41, isnot necessary. The selfpowered air heater as shown in FIGURE 2 incudes apower transmitting device 43 which receives power from engine 42 todrive several auxiliary elements including a combustion air blower 44,fan device 47, a motive fluid feed pump 53, and a fuel pump 48. Each ofthe elements can be diivingly connected to power transmitting means 43,for example by drive shaft 44a, 47a, 48a, and 53a respectively.

Combustion air blower 44 is provided to supply combustion air to theheat source included in vapor generator 41 and fan 47 is provided tomove the stream of air to be heated through condenser 40. Pump 53 isprovided to return condensed fluid from receiver 54 to vapor generator41 and fuel to be burned in working fluid generator 41 can be providedby means of a pump 48 where the fuel is delivered to inlet 52 from astorage source (not shown). It is to be noted that a fuel control valve49 can be provided to control fuel flow to vapor generator 41 inresponse to selected conditions, for example, the temperature of the airemitted from condenser 40 as measured by thermal element 51 and acondenser arrangement provided by the present invention can be used tocontrol working fluid pressure and temperature. It will be noted thatthe rate of feed of fuel to working fluid generator 51 determines therate of vaporization of fluid at selected pressure, and the quantity ofheat available to heat fluid passing through condenser 40.

As previously discussed, engine 42 receives vaporized motive fluid fromgenerator 41 to transform a portion of the pressure energy of theworking fluid to rotary motion to drive power transmitting means 43.Reduced pressure motive fluid is exhausted from engine 42 to condenser40. A portion of the vaporized motive fluid from generator 41 can beby-passed around engine 42 through by-pass 45 to maintain a constantdifferential pressure across engine 42 to selectively control poweroutput from engine 42 where by-pass 45 includes pressure responsivevalve 46 to control the differential pressure across turbine 42 and thepressure at the outlet of generator 41. The fluid which is by-passedaround engine 42 and the fluid passed through engine 42 are recombinedto flow to condenser 40 to impart heat to air passed through condenser40 in heat exchange relation. Flow of motive fluid from condenser 40 iscontrolled by valve 3 and the fluid is returned to receiver 54 to berecycled to generator 41.

As explained hereinbefore with reference to the example of FIGURE 1,condenser 40 of the heater of FIG- URE 2 can include a number ofseparate flow conduits, for example 90, 11c, 12c, and 130 Where eachseparate conduit can be connected to valve 3 through separate inletports. If a pressure responsive valve as illustrated in FIGURE 3 isused, an increase in pressure of the fluid in chamber 27 of casingindicates increased fluid pressure in condenser 40 which can, forexample, be the result of reduced rate of condensation of working fluid.The reduced rate of condensation of working fluid can result fromseveral factors including an increase in the temperature of the airsupplied to the condenser to be heated without a corresponding change inthe rate of feed of fuel to generator 41 as hereinbefore described. Thepresent invention advantageously provides an arrangement to maintainworking fluid pressure in such air heating devices to promote stableoperations while fuel feed rate corrections are made. In response to anincrease in working fluid pressure, piston 21 of valve 3 moves to openadditional conduits through condenser 40 to increase effective heattransfer area and the rate of condensation of fluid in condenser 40.Likewise, decreased fluid pressure resulting from increased rate ofcondensation, which can result from decreased temperature of the airpassing over condenser 40, causes valve 3 to close to decrease heattransfer area and increase working fluid pressure. In the application asillustrated in FIGURE 2 valve 3 can be either pressure or temperatureresponsive and can advantageously be adjusted to maintain selectedrefrigerant conditions, for example, complete condensation of motivefluid in condenser 40, or a constant downstream pressure at the outletof condenser 40.

The invention claimed is:

1. In a closed circuit through which a vaporizable-condensible workingfluid is circulated to provide a useful heating effect, the circuitincluding pump means to pump working fluid through the circuit, heatvaporizer means to vaporize the Working fluid, fluid responsive enginemeans to receive vaporized fluid to convert a portion of the energy ofsuch vaporized working fluid to useful power and a condenser means tocondense a portion of said vaporized working fluid, the presentinvention provides an improved condenser means including: condensermeans having at least two separate flow conduits to conduct workingfluid through said condenser, each conduit having an inlet tocommunicate with said source of vaporized working fluid, and a workingfluid outlet; valve means including an elongate casing having a Workingfluid outlet and working fluid inlet ports, each inlet port beingcommunicatively connected to outlets of selected flow conduits of saidcondenser means; piston means to move longitudinally through said casingto open and close selected working fluid inlet ports; and define firstchamber means between one end of said casing and said piston and secondchamber means between the other end of said casing and said piston sosaid second chamber is in communicative relation with said working fluidinlet from said casing and said fluid outlet ports; and means to movesaid piston to said casing to close off selected working fluid inletports in response to change in temperature of the working fluid admittedto the casing from said condensing means.

References Cited UNITED STATES PATENTS I 6/1915 Gibson -95 CARROLL B.DORITY, JR., Primary Examiner US. Cl. X.R. l40, 101

